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Verdoodt D, van Wijk E, Broekman S, Venselaar H, Aben F, Sels L, De Backer E, Gommeren H, Szewczyk K, Van Camp G, Ponsaerts P, Van Rompaey V, de Vrieze E. Rational design of a genomically humanized mouse model for dominantly inherited hearing loss, DFNA9. Hear Res 2024; 442:108947. [PMID: 38218018 DOI: 10.1016/j.heares.2023.108947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2023] [Revised: 12/04/2023] [Accepted: 12/30/2023] [Indexed: 01/15/2024]
Abstract
DFNA9 is a dominantly inherited form of adult-onset progressive hearing impairment caused by mutations in the COCH gene. COCH encodes cochlin, a crucial extracellular matrix protein. We established a genomically humanized mouse model for the Dutch/Belgian c.151C>T founder mutation in COCH. Considering upcoming sequence-specific genetic therapies, we exchanged the genomic murine Coch exons 3-6 for the corresponding human sequence. Introducing human-specific genetic information into mouse exons can be risky. To mitigate unforeseen consequences on cochlin function resulting from the introduction of the human COCH protein-coding sequence, we converted all human-specific amino acids to mouse equivalents. We furthermore optimized the recognition of the human COCH exons by the murine splicing machinery during pre-mRNA splicing. Subsequent observations in mouse embryonic stem cells revealed correct splicing of the hybrid Coch transcript. The inner ear of the established humanized Coch mice displays correctly-spliced wild-type and mutant humanized Coch alleles. For a comprehensive study of auditory function, mice were crossbred with C57BL/6 Cdh23753A>G mice to remove the Cdh23ahl allele from the genetic background of the mice. At 9 months, all humanized Coch genotypes showed hearing thresholds comparable to wild-type C57BL/6 Cdh23753A>G mice. This indicates that both the introduction of human wildtype COCH, and correction of Cdh23ahl in the humanized Coch lines was successful. Overall, our approach proved beneficial in eliminating potential adverse events of genomic humanization of mouse genes, and provides us with a model in which sequence-specific therapies directed against the human mutant COCH alle can be investigated. With the hearing and balance defects anticipated to occur late in the second year of life, a long-term follow-up study is ongoing to fully characterize the humanized Coch mouse model.
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Affiliation(s)
- Dorien Verdoodt
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Erwin van Wijk
- Department of Otorhinolaryngology, Hearing and Genes, Radboud University Medical Center, Nijmegen, GA 6525, the Netherlands
| | - Sanne Broekman
- Department of Otorhinolaryngology, Hearing and Genes, Radboud University Medical Center, Nijmegen, GA 6525, the Netherlands
| | - Hanka Venselaar
- Department of Medical BioSciences, Radboud University Medical Center, Nijmegen, GA 6525, the Netherlands
| | - Fien Aben
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Department of Otorhinolaryngology, Hearing and Genes, Radboud University Medical Center, Nijmegen, GA 6525, the Netherlands
| | - Lize Sels
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Evi De Backer
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Department of Otorhinolaryngology and Head & Neck Surgery, Antwerp University Hospital, Antwerp, Belgium
| | - Hanne Gommeren
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Krystyna Szewczyk
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Guy Van Camp
- Center for Medical Genetics, University of Antwerp, Antwerp 2000, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Vincent Van Rompaey
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium; Department of Otorhinolaryngology and Head & Neck Surgery, Antwerp University Hospital, Antwerp, Belgium
| | - Erik de Vrieze
- Department of Otorhinolaryngology, Hearing and Genes, Radboud University Medical Center, Nijmegen, GA 6525, the Netherlands.
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Cirilo JA, Liao X, Perrin BJ, Yengo CM. The dynamics of actin protrusions can be controlled by tip-localized myosin motors. J Biol Chem 2024; 300:105516. [PMID: 38042485 PMCID: PMC10801316 DOI: 10.1016/j.jbc.2023.105516] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/20/2023] [Accepted: 11/22/2023] [Indexed: 12/04/2023] Open
Abstract
Class III myosins localize to inner ear hair cell stereocilia and are thought to be crucial for stereocilia length regulation. Mutations within the motor domain of MYO3A that disrupt its intrinsic motor properties have been associated with non-syndromic hearing loss, suggesting that the motor properties of MYO3A are critical for its function within stereocilia. In this study, we investigated the impact of a MYO3A hearing loss mutation, H442N, using both in vitro motor assays and cell biological studies. Our results demonstrate the mutation causes a dramatic increase in intrinsic motor properties, actin-activated ATPase and in vitro actin gliding velocity, as well as an increase in actin protrusion extension velocity. We propose that both "gain of function" and "loss of function" mutations in MYO3A can impair stereocilia length regulation, which is crucial for stereocilia formation during development and normal hearing. Furthermore, we generated chimeric MYO3A constructs that replace the MYO3A motor and neck domain with the motor and neck domain of other myosins. We found that duty ratio, fraction of ATPase cycle myosin is strongly bound to actin, is a critical motor property that dictates the ability to tip localize within filopodia. In addition, in vitro actin gliding velocities correlated extremely well with filopodial extension velocities over a wide range of gliding and extension velocities. Taken together, our data suggest a model in which tip-localized myosin motors exert force that slides the membrane tip-ward, which can combat membrane tension and enhance the actin polymerization rate that ultimately drives protrusion elongation.
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Affiliation(s)
- Joseph A Cirilo
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Xiayi Liao
- Department of Biology, Indiana University - Purdue University, Indianapolis, Indiana, USA
| | - Benjamin J Perrin
- Department of Biology, Indiana University - Purdue University, Indianapolis, Indiana, USA
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA.
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3
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Wang X, Liu S, Cheng Q, Qu C, Ren R, Du H, Li N, Yan K, Wang Y, Xiong W, Xu Z. CIB2 and CIB3 Regulate Stereocilia Maintenance and Mechanoelectrical Transduction in Mouse Vestibular Hair Cells. J Neurosci 2023; 43:3219-3231. [PMID: 37001993 PMCID: PMC10162464 DOI: 10.1523/jneurosci.1807-22.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 03/20/2023] [Accepted: 03/25/2023] [Indexed: 04/03/2023] Open
Abstract
The mechanoelectrical transduction (MET) protein complex in the inner-ear hair cells is essential for hearing and balance perception. Calcium and integrin-binding protein 2 (CIB2) has been reported to be a component of MET complex, and loss of CIB2 completely abolishes MET currents in auditory hair cells, causing profound congenital hearing loss. However, loss of CIB2 does not affect MET currents in vestibular hair cells (VHCs) as well as general balance function. Here, we show that CIB2 and CIB3 act redundantly to regulate MET in VHCs, as MET currents are completely abolished in the VHCs of Cib2/Cib3 double knock-out mice of either sex. Furthermore, we show that Cib2 and Cib3 transcripts have complementary expression patterns in the vestibular maculae, and that they play different roles in stereocilia maintenance in VHCs. Cib2 transcripts are highly expressed in the striolar region, and knock-out of Cib2 affects stereocilia maintenance in striolar VHCs. In contrast, Cib3 transcripts are highly expressed in the extrastriolar region, and knock-out of Cib3 mainly affects stereocilia maintenance in extrastriolar VHCs. Simultaneous knock-out of Cib2 and Cib3 affects stereocilia maintenance in all VHCs and leads to severe balance deficits. Taken together, our present work reveals that CIB2 and CIB3 are important for stereocilia maintenance as well as MET in mouse VHCs.SIGNIFICANCE STATEMENT Calcium and integrin-binding protein 2 (CIB2) is an important component of mechanoelectrical transduction (MET) complex, and loss of CIB2 completely abolishes MET in auditory hair cells. However, MET is unaffected in Cib2 knock-out vestibular hair cells (VHCs). In the present work, we show that CIB3 could compensate for the loss of CIB2 in VHCs, and Cib2/Cib3 double knock-out completely abolishes MET in VHCs. Interestingly, CIB2 and CIB3 could also regulate VHC stereocilia maintenance in a nonredundant way. Cib2 and Cib3 transcripts are highly expressed in the striolar and extrastriolar regions, respectively. Stereocilia maintenance and balance function are differently affected in Cib2 or Cib3 knock-out mice. In conclusion, our data suggest that CIB2 and CIB3 are important for stereocilia maintenance and MET in mouse VHCs.
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Affiliation(s)
- Xiaoying Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Shuang Liu
- School of Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, People's Republic of China
- Chinese Institute for Brain Research, Beijing 102206, People's Republic of China
| | - Qi Cheng
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Chengli Qu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Rui Ren
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Nana Li
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Keji Yan
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
| | - Wei Xiong
- School of Life Sciences, IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing 100084, People's Republic of China
- Chinese Institute for Brain Research, Beijing 102206, People's Republic of China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cells and Developmental Biology and Key Laboratory for Experimental Teratology of the Ministry of Education, School of Life Sciences, Shandong University, Qingdao, Shandong 266237, People's Republic of China
- Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, Shandong 250014, People's Republic of China
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Wang H, Du H, Ren R, Du T, Lin L, Feng Z, Zhao D, Wei X, Zhai X, Wang H, Dong T, Sun JP, Wu H, Xu Z, Lu Q. Temporal and spatial assembly of inner ear hair cell ankle link condensate through phase separation. Nat Commun 2023; 14:1657. [PMID: 36964137 PMCID: PMC10039067 DOI: 10.1038/s41467-023-37267-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Accepted: 03/09/2023] [Indexed: 03/26/2023] Open
Abstract
Stereocilia are actin-based cell protrusions of inner ear hair cells and are indispensable for mechanotransduction. Ankle links connect the ankle region of developing stereocilia, playing an essential role in stereocilia development. WHRN, PDZD7, ADGRV1 and USH2A have been identified to form the so-called ankle link complex (ALC); however, the detailed mechanism underlying the temporal emergence and degeneration of ankle links remains elusive. Here we show that WHRN and PDZD7 orchestrate ADGRV1 and USH2A to assemble the ALC through liquid-liquid phase separation (LLPS). Disruption of the ALC multivalency for LLPS largely abolishes the distribution of WHRN at the ankle region of stereocilia. Interestingly, high concentration of ADGRV1 inhibits LLPS, providing a potential mechanism for ALC disassembly. Moreover, certain deafness mutations of ALC genes weaken the multivalent interactions of ALC and impair LLPS. In conclusion, our study demonstrates that LLPS mediates ALC formation, providing essential clues for understanding the pathogenesis of deafness.
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Affiliation(s)
- Huang Wang
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Haibo Du
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China
- Air Force Medical Center, PLA, Beijing, 100074, China
| | - Rui Ren
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China
| | - Tingting Du
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Lin Lin
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Zhe Feng
- School of Life Sciences, Fudan University, Shanghai, 200433, China
| | - Dange Zhao
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xiaoxi Wei
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200030, China
| | - Xiaoyan Zhai
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China
| | - Hongyang Wang
- College of Otolaryngology, Head and Neck Surgery, Department of Audiology and Vestibular Medicine, Chinese PLA Institute of Otolaryngology, Chinese PLA General Hospital, Medical School of Chinese PLA, 28 Fuxing Road, 100853, Beijing, China
- National Clinical Research Center for Otolaryngologic Diseases, Chinese PLA General Hospital, Medical School of Chinese PLA, 28 Fuxing Road, 100853, Beijing, China
| | - Tingting Dong
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Jin-Peng Sun
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Cheeloo College of Medicine, Shandong University, Jinan, China
| | - Hao Wu
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, Shandong, 266237, China.
- Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, Shandong, 250014, China.
| | - Qing Lu
- Key Laboratory for the Genetics of Developmental and Neuropsychiatric Disorders, Ministry of Education, Bio-X Institutes, Shanghai Jiao Tong University, Shanghai, 200030, China.
- Department of Otolaryngology-Head and Neck Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Ear Institute, Shanghai Jiao Tong University School of Medicine, Shanghai, China. Shanghai Key Laboratory of Translational Medicine on Ear and Nose Diseases, Shanghai, China.
- Bio-X-Renji Hospital Research Center, School of Medicine, Renji Hospital, Shanghai Jiao Tong University, Shanghai, China.
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5
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The tetraspan LHFPL5 is critical to establish maximal force sensitivity of the mechanotransduction channel of cochlear hair cells. Cell Rep 2023; 42:112245. [PMID: 36917610 DOI: 10.1016/j.celrep.2023.112245] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2022] [Revised: 01/28/2023] [Accepted: 02/27/2023] [Indexed: 03/14/2023] Open
Abstract
The mechanoelectrical transduction (MET) channel of cochlear hair cells is gated by the tip link, but the mechanisms that establish the exquisite force sensitivity of this MET channel are not known. Here, we show that the tetraspan lipoma HMGIC fusion partner-like 5 (LHFPL5) directly couples the tip link to the MET channel. Disruption of these interactions severely perturbs MET. Notably, the N-terminal cytoplasmic domain of LHFPL5 binds to an amphipathic helix in TMC1, a critical gating domain conserved between different MET channels. Mutations in the amphipathic helix of TMC1 or in the N-terminus of LHFPL5 that perturb interactions of LHFPL5 with the amphipathic helix affect channel responses to mechanical force. We conclude that LHFPL5 couples the tip link to the MET channel and that channel gating depends on a structural element in TMC1 that is evolutionarily conserved between MET channels. Overall, our findings support a tether model for transduction channel gating by the tip link.
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Liu L, Zou L, Li K, Hou H, Hu Q, Liu S, Li J, Song C, Chen J, Wang S, Wang Y, Li C, Du H, Li JL, Chen F, Xu Z, Sun W, Sun Q, Xiong W. Template-independent genome editing in the Pcdh15 av-3j mouse, a model of human DFNB23 nonsyndromic deafness. Cell Rep 2022; 40:111061. [PMID: 35830793 DOI: 10.1016/j.celrep.2022.111061] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2021] [Revised: 04/15/2022] [Accepted: 06/14/2022] [Indexed: 11/03/2022] Open
Abstract
Although frameshift mutations lead to 22% of inherited Mendelian disorders in humans, there is no efficient in vivo gene therapy strategy available to date, particularly in nondividing cells. Here, we show that nonhomologous end-joining (NHEJ)-mediated nonrandom editing profiles compensate the frameshift mutation in the Pcdh15 gene and restore the lost mechanotransduction function in postmitotic hair cells of Pcdh15av-3J mice, an animal model of human nonsyndromic deafness DFNB23. Identified by an ex vivo evaluation system in cultured cochlear explants, the selected guide RNA restores reading frame in approximately 50% of indel products and recovers mechanotransduction in more than 70% of targeted hair cells. In vivo treatment shows that half of the animals gain improvements in auditory responses, and balance function is restored in the majority of injected mutant mice. These results demonstrate that NHEJ-mediated reading-frame restoration is a simple and efficient strategy in postmitotic systems.
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Affiliation(s)
- Lian Liu
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Kuan Li
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Hanqing Hou
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Qun Hu
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Shuang Liu
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Jie Li
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Chenmeng Song
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Jiaofeng Chen
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Yangzhen Wang
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China
| | - Changri Li
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Haibo Du
- School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Jun-Liszt Li
- Chinese Institute for Brain Research, Beijing 102206, China; Academy for Advanced Interdisciplinary Studies (AAIS), Peking University, Beijing 100871, China
| | - Fangyi Chen
- Department of Biomedical Engineering, Southern University of Science and Technology, Shenzhen, Guangdong 518055, China
| | - Zhigang Xu
- School of Life Sciences, Shandong University, Qingdao, Shandong 266237, China
| | - Wenzhi Sun
- Chinese Institute for Brain Research, Beijing 102206, China; School of Basic Medical Sciences, Capital Medical University, Beijing 100069, China
| | - Qianwen Sun
- School of Life Sciences, Tsinghua University, Beijing 100084, China; Tsinghua-Peking Joint Center for Life Sciences, Tsinghua University, Beijing 100084, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, Beijing 100084, China; IDG/McGovern Institute for Brain Research at Tsinghua University, Tsinghua University, Beijing 100084, China.
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7
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Krey JF, Liu C, Belyantseva IA, Bateschell M, Dumont RA, Goldsmith J, Chatterjee P, Morrill RS, Fedorov LM, Foster S, Kim J, Nuttall AL, Jones SM, Choi D, Friedman TB, Ricci AJ, Zhao B, Barr-Gillespie PG. ANKRD24 organizes TRIOBP to reinforce stereocilia insertion points. J Cell Biol 2022; 221:e202109134. [PMID: 35175278 PMCID: PMC8859912 DOI: 10.1083/jcb.202109134] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2021] [Revised: 01/07/2022] [Accepted: 01/21/2022] [Indexed: 01/04/2023] Open
Abstract
The stereocilia rootlet is a key structure in vertebrate hair cells, anchoring stereocilia firmly into the cell's cuticular plate and protecting them from overstimulation. Using superresolution microscopy, we show that the ankyrin-repeat protein ANKRD24 concentrates at the stereocilia insertion point, forming a ring at the junction between the lower and upper rootlets. Annular ANKRD24 continues into the lower rootlet, where it surrounds and binds TRIOBP-5, which itself bundles rootlet F-actin. TRIOBP-5 is mislocalized in Ankrd24KO/KO hair cells, and ANKRD24 no longer localizes with rootlets in mice lacking TRIOBP-5; exogenous DsRed-TRIOBP-5 restores endogenous ANKRD24 to rootlets in these mice. Ankrd24KO/KO mice show progressive hearing loss and diminished recovery of auditory function after noise damage, as well as increased susceptibility to overstimulation of the hair bundle. We propose that ANKRD24 bridges the apical plasma membrane with the lower rootlet, maintaining a normal distribution of TRIOBP-5. Together with TRIOBP-5, ANKRD24 organizes rootlets to enable hearing with long-term resilience.
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Affiliation(s)
- Jocelyn F. Krey
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Chang Liu
- Department of Otolaryngology—Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN
| | - Inna A. Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Michael Bateschell
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Rachel A. Dumont
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Jennifer Goldsmith
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Paroma Chatterjee
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Rachel S. Morrill
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
| | - Lev M. Fedorov
- Transgenic Mouse Models, University Shared Resources Program, Oregon Health & Science University, Portland, OR
| | - Sarah Foster
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
| | - Jinkyung Kim
- Department of Otolaryngology—Head & Neck Surgery, Stanford University, Stanford, CA
| | - Alfred L. Nuttall
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
| | - Sherri M. Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | - Dongseok Choi
- OHSU-PSU School of Public Health, Oregon Health & Science University, Portland, OR
| | - Thomas B. Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD
| | - Anthony J. Ricci
- Department of Otolaryngology—Head & Neck Surgery, Stanford University, Stanford, CA
| | - Bo Zhao
- Department of Otolaryngology—Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN
| | - Peter G. Barr-Gillespie
- Oregon Hearing Research Center, Oregon Health & Science University, Portland, OR
- Vollum Institute, Oregon Health & Science University, Portland, OR
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8
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Tu H, Zhang A, Fu X, Xu S, Bai X, Wang H, Gao J. SMPX Deficiency Causes Stereocilia Degeneration and Progressive Hearing Loss in CBA/CaJ Mice. Front Cell Dev Biol 2021; 9:750023. [PMID: 34722533 PMCID: PMC8551870 DOI: 10.3389/fcell.2021.750023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 09/17/2021] [Indexed: 11/13/2022] Open
Abstract
The small muscle protein, x-linked (SMPX) encodes a small protein containing 88 amino acids. Malfunction of this protein can cause a sex-linked non-syndromic hearing loss, named X-linked deafness 4 (DFNX4). Herein, we reported a point mutation and a frameshift mutation in two Chinese families who developed gradual hearing loss with age. To explore the impaired sites in the hearing system and the mechanism of DFNX4, we established and validated an Smpx null mouse model using CRISPR-Cas9. By analyzing auditory brainstem response (ABR), male Smpx null mice showed a progressive hearing loss starting from high frequency at the 3rd month. Hearing loss in female mice was milder and occurred later compared to male mice, which was very similar to human beings. Through morphological analyses of mice cochleas, we found the hair cell bundles progressively degenerated from the shortest row. Cellular edema occurred at the end phase of stereocilia degeneration, followed by cell death. By transfecting exogenous fluorescent Smpx into living hair cells, Smpx was observed to be expressed in stereocilia. Through noise exposure, it was shown that Smpx might participate in maintaining hair cell bundles. This Smpx knock-out mouse might be used as a suitable model to explore the pathology of DFNX4.
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Affiliation(s)
- Hailong Tu
- School of Life Sciences, Shandong Provincial ENT Hospital, Shandong University, Jinan, China
| | - Aizhen Zhang
- School of Life Sciences, Shandong Provincial ENT Hospital, Shandong University, Jinan, China
| | - Xiaolong Fu
- School of Life Sciences, Shandong Provincial ENT Hospital, Shandong University, Jinan, China
| | - Shiqi Xu
- University of Edinburgh Institute, Zhejiang University School of Medicine, Zhejiang University, Haining, China
| | - Xiaohui Bai
- Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Jinan, China
| | - Haibo Wang
- School of Life Sciences, Shandong Provincial ENT Hospital, Shandong University, Jinan, China.,Otolaryngology-Head and Neck Surgery, Shandong Provincial ENT Hospital, Jinan, China
| | - Jiangang Gao
- School of Life Sciences, Shandong Provincial ENT Hospital, Shandong University, Jinan, China
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9
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Liang X, Qiu X, Dionne G, Cunningham CL, Pucak ML, Peng G, Kim YH, Lauer A, Shapiro L, Müller U. CIB2 and CIB3 are auxiliary subunits of the mechanotransduction channel of hair cells. Neuron 2021; 109:2131-2149.e15. [PMID: 34089643 PMCID: PMC8374959 DOI: 10.1016/j.neuron.2021.05.007] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Revised: 01/17/2021] [Accepted: 05/07/2021] [Indexed: 12/25/2022]
Abstract
CIB2 is a Ca2+- and Mg2+-binding protein essential for mechanoelectrical transduction (MET) by cochlear hair cells, but not by vestibular hair cells that co-express CIB2 and CIB3. Here, we show that in cochlear hair cells, CIB3 can functionally substitute for CIB2. Using X-ray crystallography, we demonstrate that CIB2 and CIB3 are structurally similar to KChIP proteins, auxiliary subunits of voltage-gated Kv4 channels. CIB2 and CIB3 bind to TMC1/2 through a domain in TMC1/2 flanked by transmembrane domains 2 and 3. The co-crystal structure of the CIB-binding domain in TMC1 with CIB3 reveals that interactions are mediated through a conserved CIB hydrophobic groove, similar to KChIP1 binding of Kv4. Functional studies in mice show that CIB2 regulates TMC1/2 localization and function in hair cells, processes that are affected by deafness-causing CIB2 mutations. We conclude that CIB2 and CIB3 are MET channel auxiliary subunits with striking similarity to Kv4 channel auxiliary subunits.
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Affiliation(s)
- Xiaoping Liang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Gilman Dionne
- Department of Biochemistry and Molecular Biophysics, Zuckerman Mind Brain, Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Christopher L Cunningham
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Michele L Pucak
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guihong Peng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ye-Hyun Kim
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amanda Lauer
- Department of Otolaryngology-HNS, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Zuckerman Mind Brain, Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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10
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Li J, Liu C, Zhao B. N-Terminus of GRXCR2 Interacts With CLIC5 and Is Essential for Auditory Perception. Front Cell Dev Biol 2021; 9:671364. [PMID: 34026762 PMCID: PMC8131845 DOI: 10.3389/fcell.2021.671364] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Accepted: 04/13/2021] [Indexed: 11/17/2022] Open
Abstract
Stereocilia of cochlear hair cells are specialized mechanosensing organelles that convert sound-induced vibration to electrical signals. Glutaredoxin domain-containing cysteine-rich protein 2 (GRXCR2) is localized at the base of stereocilia and is necessary for stereocilia morphogenesis and auditory perception. However, the detailed functions of GRXCR2 in hair cells are still largely unknown. Here, we report that GRXCR2 interacts with chloride intracellular channel protein 5 (CLIC5) which is also localized at the base of stereocilia and required for normal hearing in human and mouse. Immunolocalization analyses suggest that GRXCR2 is not required for the localization of CLIC5 to the stereociliary base during development, or vice versa. Using clustered regularly interspaced short palindromic repeats (CRISPR)/Cas9 system, we deleted 60 amino acids near the N-terminus of GRXCR2 essential for its interaction with CLIC5. Interestingly, mice harboring this in-frame deletion in Grxcr2 exhibit moderate hearing loss at lower frequencies and severe hearing loss at higher frequencies although the morphogenesis of stereocilia is minimally affected. Thus, our findings reveal that the interaction between GRXCR2 and CLIC5 is crucial for normal hearing.
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Affiliation(s)
- Jinan Li
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Chang Liu
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
| | - Bo Zhao
- Department of Otolaryngology-Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, IN, United States
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11
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Miyoshi T, Zhang Q, Miyake T, Watanabe S, Ohnishi H, Chen J, Vishwasrao HD, Chakraborty O, Belyantseva IA, Perrin BJ, Shroff H, Friedman TB, Omori K, Watanabe N. Semi-automated single-molecule microscopy screening of fast-dissociating specific antibodies directly from hybridoma cultures. Cell Rep 2021; 34:108708. [PMID: 33535030 PMCID: PMC7904085 DOI: 10.1016/j.celrep.2021.108708] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2020] [Revised: 07/16/2020] [Accepted: 01/08/2021] [Indexed: 11/18/2022] Open
Abstract
Fast-dissociating, specific antibodies are single-molecule imaging probes that transiently interact with their targets and are used in biological applications including image reconstruction by integrating exchangeable single-molecule localization (IRIS), a multiplexable super-resolution microscopy technique. Here, we introduce a semi-automated screen based on single-molecule total internal reflection fluorescence (TIRF) microscopy of antibody-antigen binding, which allows for identification of fast-dissociating monoclonal antibodies directly from thousands of hybridoma cultures. We develop monoclonal antibodies against three epitope tags (FLAG-tag, S-tag, and V5-tag) and two F-actin crosslinking proteins (plastin and espin). Specific antibodies show fast dissociation with half-lives ranging from 0.98 to 2.2 s. Unexpectedly, fast-dissociating yet specific antibodies are not so rare. A combination of fluorescently labeled Fab probes synthesized from these antibodies and light-sheet microscopy, such as dual-view inverted selective plane illumination microscopy (diSPIM), reveal rapid turnover of espin within long-lived F-actin cores of inner-ear sensory hair cell stereocilia, demonstrating that fast-dissociating specific antibodies can identify novel biological phenomena.
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Affiliation(s)
- Takushi Miyoshi
- Laboratory of Single-Molecule Cell Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan; Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Department of Otolaryngology - Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan; Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA.
| | - Qianli Zhang
- Laboratory of Single-Molecule Cell Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Takafumi Miyake
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan; Department of Nephrology, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Shin Watanabe
- Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan
| | - Hiroe Ohnishi
- Department of Otolaryngology - Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Jiji Chen
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD 20892, USA
| | - Harshad D Vishwasrao
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD 20892, USA
| | - Oisorjo Chakraborty
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Inna A Belyantseva
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Benjamin J Perrin
- Department of Biology, Indiana University-Purdue University Indianapolis, Indianapolis, IN 46202, USA
| | - Hari Shroff
- Advanced Imaging and Microscopy Resource, National Institutes of Health, Bethesda, MD 20892, USA; Laboratory of High Resolution Optical Imaging, National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA
| | - Thomas B Friedman
- Laboratory of Molecular Genetics, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD 20892, USA
| | - Koichi Omori
- Department of Otolaryngology - Head and Neck Surgery, Graduate School of Medicine, Kyoto University, Kyoto 606-8507, Japan
| | - Naoki Watanabe
- Laboratory of Single-Molecule Cell Biology, Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan; Department of Pharmacology, Graduate School of Medicine, Kyoto University, Kyoto 606-8501, Japan.
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12
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Cunningham CL, Qiu X, Wu Z, Zhao B, Peng G, Kim YH, Lauer A, Müller U. TMIE Defines Pore and Gating Properties of the Mechanotransduction Channel of Mammalian Cochlear Hair Cells. Neuron 2020; 107:126-143.e8. [PMID: 32343945 PMCID: PMC7351599 DOI: 10.1016/j.neuron.2020.03.033] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 02/24/2020] [Accepted: 03/30/2020] [Indexed: 12/29/2022]
Abstract
TMC1 and TMC2 (TMC1/2) have been proposed to form the pore of the mechanotransduction channel of cochlear hair cells. Here, we show that TMC1/2 cannot form mechanotransduction channels in cochlear hair cells without TMIE. TMIE binds to TMC1/2, and a TMIE mutation that perturbs TMC1/2 binding abolishes mechanotransduction. N-terminal TMIE deletions affect the response of the mechanotransduction channel to mechanical force. Similar to mechanically gated TREK channels, the C-terminal cytoplasmic TMIE domain contains charged amino acids that mediate binding to phospholipids, including PIP2. TMIE point mutations in the C terminus that are linked to deafness disrupt phospholipid binding, sensitize the channel to PIP2 depletion from hair cells, and alter the channel's unitary conductance and ion selectivity. We conclude that TMIE is a subunit of the cochlear mechanotransduction channel and that channel function is regulated by a phospholipid-sensing domain in TMIE with similarity to those in other mechanically gated ion channels.
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Affiliation(s)
- Christopher L Cunningham
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Zizhen Wu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bo Zhao
- Department of Otolaryngology - Head & Neck Surgery, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Guihong Peng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ye-Hyun Kim
- Department of Otolaryngology - HNS, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Amanda Lauer
- Department of Otolaryngology - HNS, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
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13
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Kleinlogel S, Vogl C, Jeschke M, Neef J, Moser T. Emerging approaches for restoration of hearing and vision. Physiol Rev 2020; 100:1467-1525. [DOI: 10.1152/physrev.00035.2019] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Impairments of vision and hearing are highly prevalent conditions limiting the quality of life and presenting a major socioeconomic burden. For long, retinal and cochlear disorders have remained intractable for causal therapies, with sensory rehabilitation limited to glasses, hearing aids, and electrical cochlear or retinal implants. Recently, the application of gene therapy and optogenetics to eye and ear has generated hope for a fundamental improvement of vision and hearing restoration. To date, one gene therapy for the restoration of vision has been approved and undergoing clinical trials will broaden its application including gene replacement, genome editing, and regenerative approaches. Moreover, optogenetics, i.e. controlling the activity of cells by light, offers a more general alternative strategy. Over little more than a decade, optogenetic approaches have been developed and applied to better understand the function of biological systems, while protein engineers have identified and designed new opsin variants with desired physiological features. Considering potential clinical applications of optogenetics, the spotlight is on the sensory systems. Multiple efforts have been undertaken to restore lost or hampered function in eye and ear. Optogenetic stimulation promises to overcome fundamental shortcomings of electrical stimulation, namely poor spatial resolution and cellular specificity, and accordingly to deliver more detailed sensory information. This review aims at providing a comprehensive reference on current gene therapeutic and optogenetic research relevant to the restoration of hearing and vision. We will introduce gene-therapeutic approaches and discuss the biotechnological and optoelectronic aspects of optogenetic hearing and vision restoration.
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Affiliation(s)
| | | | | | | | - Tobias Moser
- Institute for Auditory Neuroscience, University Medical Center Goettingen, Germany
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14
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GRXCR2 Regulates Taperin Localization Critical for Stereocilia Morphology and Hearing. Cell Rep 2019; 25:1268-1280.e4. [PMID: 30380417 PMCID: PMC6317715 DOI: 10.1016/j.celrep.2018.09.063] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 09/03/2018] [Accepted: 09/19/2018] [Indexed: 12/14/2022] Open
Abstract
Mutations in human GRXCR2, which encodes a protein of undetermined function, cause hearing loss by unknown mechanisms. We found that mouse GRXCR2 localizes to the base of the stereocilia, which are actin-based mechanosensing organelles in cochlear hair cells that convert sound-induced vibrations into electrical signals. The stereocilia base also contains taperin, another protein of unknown function required for human hearing. We show that taperin and GRXCR2 form a complex and that taperin is diffused throughout the stereocilia length in Grxcr2-deficient hair cells. Stereocilia lacking GRXCR2 are longer than normal and disorganized due to the mislocalization of taperin, which could modulate the actin cytoskeleton in stereocilia. Remarkably, reducing taperin expression levels could rescue the morphological defects of stereocilia and restore the hearing of Grxcr2-deficient mice. Thus, our findings suggest that GRXCR2 is critical for the morphogenesis of stereocilia and auditory perception by restricting taperin to the stereocilia base. Liu et al. show that GRXCR2 and taperin form a complex at the base of the stereocilia in cochlear hair cells. Stereocilia lacking GRXCR2 are longer than normal and disorganized due to the mislocalization of taperin, which could modulate the actin cytoskeleton in stereocilia. Reducing taperin expression levels could rescue the morphological defects of stereocilia and restore the hearing of Grxcr2-deficient mice.
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15
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Du H, Zou L, Ren R, Li N, Li J, Wang Y, Sun J, Yang J, Xiong W, Xu Z. Lack of PDZD7 long isoform disrupts ankle-link complex and causes hearing loss in mice. FASEB J 2019; 34:1136-1149. [PMID: 31914662 DOI: 10.1096/fj.201901657rr] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 09/28/2019] [Accepted: 11/14/2019] [Indexed: 12/12/2022]
Abstract
Usher syndrome (USH) is the most frequent form of combined hereditary deafness-blindness, characterized by hearing loss and retinitis pigmentosa, with or without vestibular dysfunction. PDZD7 is a PDZ domain-containing scaffold protein that was suggested to be a USH modifier and a contributor to digenic USH. In the inner ear hair cells, PDZD7 localizes at the ankle region of the stereocilia and constitutes the so-called ankle-link complex together with three other USH proteins Usherin, WHRN, and ADGRV1. PDZD7 gene is subjected to alternative splicing, which gives rise to two types of PDZD7 isoforms, namely the long and short isoforms. At present, little is known which specific isoform is involved in ankle-link formation and stereocilia development. In this work, we showed that PDZD7 long isoform, but not short isoforms, localizes at the ankle region of the stereocilia. Moreover, we established Pdzd7 mutant mice by introducing deletions into exon 14 of the Pdzd7 gene, which causes potential premature translational stop in the long isoform but leaves short isoforms unaffected. We found that lack of PDZD7 long isoform affects the localization of other ankle-link complex components in the stereocilia. Consequently, Pdzd7 mutant mice showed stereocilia development deficits and hearing loss as well as reduced mechanotransduction (MET) currents, suggesting that PDZD7 long isoform is indispensable for hair cells. Furthermore, by performing yeast two-hybrid screening, we identified a PDZD7 long isoform-specific binding partner PIP5K1C, which has been shown to play important roles in hearing and might participate in the function and/or transportation of PDZD7.
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Affiliation(s)
- Haibo Du
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Linzhi Zou
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Rui Ren
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Nana Li
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Jie Li
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Yanfei Wang
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China
| | - Jinpeng Sun
- Key Laboratory Experimental Teratology of the Ministry of Education, Department of Biochemistry and Molecular Biology, Shandong University School of Medicine, Jinan, China
| | - Jun Yang
- Department of Ophthalmology and Visual Sciences, Moran Eye Center, University of Utah, Salt Lake City, Utah
| | - Wei Xiong
- School of Life Sciences, IDG/McGovern Institute for Brain Research at Tsinghua, Tsinghua University, Beijing, China
| | - Zhigang Xu
- Shandong Provincial Key Laboratory of Animal Cell and Developmental Biology, School of Life Sciences, Shandong University, Qingdao, China.,Shandong Provincial Collaborative Innovation Center of Cell Biology, Shandong Normal University, Jinan, China
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16
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Liu S, Wang S, Zou L, Li J, Song C, Chen J, Hu Q, Liu L, Huang P, Xiong W. TMC1 is an essential component of a leak channel that modulates tonotopy and excitability of auditory hair cells in mice. eLife 2019; 8:47441. [PMID: 31661074 PMCID: PMC6853638 DOI: 10.7554/elife.47441] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2019] [Accepted: 10/24/2019] [Indexed: 11/13/2022] Open
Abstract
Hearing sensation relies on the mechano-electrical transducer (MET) channel of cochlear hair cells, in which transmembrane channel-like 1 (TMC1) and transmembrane channel-like 2 (TMC2) have been proposed to be the pore-forming subunits in mammals. TMCs were also found to regulate biological processes other than MET in invertebrates, ranging from sensations to motor function. However, whether TMCs have a non-MET role remains elusive in mammals. Here, we report that in mouse hair cells, TMC1, but not TMC2, provides a background leak conductance, with properties distinct from those of the MET channels. By cysteine substitutions in TMC1, we characterized four amino acids that are required for the leak conductance. The leak conductance is graded in a frequency-dependent manner along the length of the cochlea and is indispensable for action potential firing. Taken together, our results show that TMC1 confers a background leak conductance in cochlear hair cells, which may be critical for the acquisition of sound-frequency and -intensity.
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Affiliation(s)
- Shuang Liu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Shufeng Wang
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Jie Li
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Chenmeng Song
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Jiaofeng Chen
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Qun Hu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Lian Liu
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
| | - Pingbo Huang
- Department of Chemical and Biological Engineering, Hong Kong University of Science and Technology, Hong Kong, China.,State Key Laboratory of Molecular Neuroscience, Hong Kong University of Science and Technology, Hong Kong, China.,Division of Life Science, Hong Kong University of Science and Technology, Hong Kong, China
| | - Wei Xiong
- School of Life Sciences, Tsinghua University, Beijing, China.,IDG/McGovern Institute for Brain Research at Tsinghua University, Beijing, China
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17
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Dunbar LA, Patni P, Aguilar C, Mburu P, Corns L, Wells HRR, Delmaghani S, Parker A, Johnson S, Williams D, Esapa CT, Simon MM, Chessum L, Newton S, Dorning J, Jeyarajan P, Morse S, Lelli A, Codner GF, Peineau T, Gopal SR, Alagramam KN, Hertzano R, Dulon D, Wells S, Williams FM, Petit C, Dawson SJ, Brown SDM, Marcotti W, El‐Amraoui A, Bowl MR. Clarin-2 is essential for hearing by maintaining stereocilia integrity and function. EMBO Mol Med 2019; 11:e10288. [PMID: 31448880 PMCID: PMC6728604 DOI: 10.15252/emmm.201910288] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2019] [Revised: 07/23/2019] [Accepted: 07/26/2019] [Indexed: 11/21/2022] Open
Abstract
Hearing relies on mechanically gated ion channels present in the actin-rich stereocilia bundles at the apical surface of cochlear hair cells. Our knowledge of the mechanisms underlying the formation and maintenance of the sound-receptive structure is limited. Utilizing a large-scale forward genetic screen in mice, genome mapping and gene complementation tests, we identified Clrn2 as a new deafness gene. The Clrn2clarinet/clarinet mice (p.Trp4* mutation) exhibit a progressive, early-onset hearing loss, with no overt retinal deficits. Utilizing data from the UK Biobank study, we could show that CLRN2 is involved in human non-syndromic progressive hearing loss. Our in-depth morphological, molecular and functional investigations establish that while it is not required for initial formation of cochlear sensory hair cell stereocilia bundles, clarin-2 is critical for maintaining normal bundle integrity and functioning. In the differentiating hair bundles, lack of clarin-2 leads to loss of mechano-electrical transduction, followed by selective progressive loss of the transducing stereocilia. Together, our findings demonstrate a key role for clarin-2 in mammalian hearing, providing insights into the interplay between mechano-electrical transduction and stereocilia maintenance.
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Affiliation(s)
- Lucy A Dunbar
- Mammalian Genetics UnitMRC Harwell InstituteHarwellUK
| | - Pranav Patni
- Déficits Sensoriels ProgressifsInstitut PasteurINSERM UMR‐S 1120Sorbonne UniversitésParisFrance
| | | | | | - Laura Corns
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - Helena RR Wells
- Department of Twin Research & Genetic EpidemiologyKing's College LondonLondonUK
| | - Sedigheh Delmaghani
- Déficits Sensoriels ProgressifsInstitut PasteurINSERM UMR‐S 1120Sorbonne UniversitésParisFrance
| | - Andrew Parker
- Mammalian Genetics UnitMRC Harwell InstituteHarwellUK
| | - Stuart Johnson
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | | | | | | | | | | | | | | | - Susan Morse
- Mammalian Genetics UnitMRC Harwell InstituteHarwellUK
| | - Andrea Lelli
- Génétique et Physiologie de l'AuditionInstitut PasteurINSERM UMR‐S 1120Collège de FranceSorbonne UniversitésParisFrance
| | | | - Thibault Peineau
- Laboratoire de Neurophysiologie de la Synapse AuditiveUniversité de BordeauxBordeauxFrance
| | - Suhasini R Gopal
- Department of Otolaryngology – Head and Neck SurgeryUniversity Hospitals Cleveland Medical CenterCase Western Reserve UniversityClevelandOHUSA
| | - Kumar N Alagramam
- Department of Otolaryngology – Head and Neck SurgeryUniversity Hospitals Cleveland Medical CenterCase Western Reserve UniversityClevelandOHUSA
| | - Ronna Hertzano
- Department of Otorhinolaryngology Head and Neck Surgery, Anatomy and Neurobiology and Institute for Genome SciencesUniversity of Maryland School of MedicineBaltimoreMDUSA
| | - Didier Dulon
- Laboratoire de Neurophysiologie de la Synapse AuditiveUniversité de BordeauxBordeauxFrance
| | - Sara Wells
- Mary Lyon CentreMRC Harwell InstituteHarwellUK
| | - Frances M Williams
- Department of Twin Research & Genetic EpidemiologyKing's College LondonLondonUK
| | - Christine Petit
- Génétique et Physiologie de l'AuditionInstitut PasteurINSERM UMR‐S 1120Collège de FranceSorbonne UniversitésParisFrance
| | | | | | - Walter Marcotti
- Department of Biomedical ScienceUniversity of SheffieldSheffieldUK
| | - Aziz El‐Amraoui
- Déficits Sensoriels ProgressifsInstitut PasteurINSERM UMR‐S 1120Sorbonne UniversitésParisFrance
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18
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Pinyon JL, von Jonquieres G, Crawford EN, Duxbury M, Al Abed A, Lovell NH, Klugmann M, Wise AK, Fallon JB, Shepherd RK, Birman CS, Lai W, McAlpine D, McMahon C, Carter PM, Enke YL, Patrick JF, Schilder AG, Marie C, Scherman D, Housley GD. Neurotrophin gene augmentation by electrotransfer to improve cochlear implant hearing outcomes. Hear Res 2019; 380:137-149. [DOI: 10.1016/j.heares.2019.06.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2019] [Revised: 06/07/2019] [Accepted: 06/12/2019] [Indexed: 12/14/2022]
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19
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Dionne G, Qiu X, Rapp M, Liang X, Zhao B, Peng G, Katsamba PS, Ahlsen G, Rubinstein R, Potter CS, Carragher B, Honig B, Müller U, Shapiro L. Mechanotransduction by PCDH15 Relies on a Novel cis-Dimeric Architecture. Neuron 2018; 99:480-492.e5. [PMID: 30057206 PMCID: PMC6168201 DOI: 10.1016/j.neuron.2018.07.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2018] [Revised: 06/06/2018] [Accepted: 06/29/2018] [Indexed: 10/28/2022]
Abstract
The tip link, a filament formed by protocadherin 15 (PCDH15) and cadherin 23, conveys mechanical force from sound waves and head movement to open hair-cell mechanotransduction channels. Tip-link cadherins are thought to have acquired structural features critical for their role in mechanotransduction. Here, we biophysically and structurally characterize the unusual cis-homodimeric architecture of PCDH15. We show that PCDH15 molecules form double-helical assemblies through cis-dimerization interfaces in the extracellular cadherin EC2-EC3 domain region and in a unique membrane-proximal domain. Electron microscopy studies visualize the cis-dimeric PCDH15 assembly and reveal the PCDH15 extracellular domain as a parallel double helix with cis cross-bridges at the two locations we defined. The helical configuration suggests the potential for elasticity through helix winding and unwinding. Functional studies in hair cells show that mutations that perturb PCDH15 dimerization contacts affect mechanotransduction. Together, these data reveal the cis-dimeric architecture of PCDH15 and show that dimerization is critical for sensing mechanical stimuli.
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Affiliation(s)
- Gilman Dionne
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA
| | - Xufeng Qiu
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Micah Rapp
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Xiaoping Liang
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Bo Zhao
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Guihong Peng
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Phinikoula S Katsamba
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Goran Ahlsen
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA
| | - Rotem Rubinstein
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA
| | - Clinton S Potter
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Bridget Carragher
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; National Resource for Automated Molecular Microscopy, Simons Electron Microscopy Center, New York Structural Biology Center, New York, NY 10027, USA
| | - Barry Honig
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Howard Hughes Medical Institute, Columbia University, New York, NY 10032, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
| | - Ulrich Müller
- The Solomon H. Snyder Department of Neuroscience, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA.
| | - Lawrence Shapiro
- Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY 10032, USA; Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, USA; Department of Systems Biology, Columbia University, New York, NY 10032, USA.
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20
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Yang Y, Liu N, He Y, Liu Y, Ge L, Zou L, Song S, Xiong W, Liu X. Improved calcium sensor GCaMP-X overcomes the calcium channel perturbations induced by the calmodulin in GCaMP. Nat Commun 2018; 9:1504. [PMID: 29666364 PMCID: PMC5904127 DOI: 10.1038/s41467-018-03719-6] [Citation(s) in RCA: 106] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2017] [Accepted: 03/09/2018] [Indexed: 01/09/2023] Open
Abstract
GCaMP, one popular type of genetically-encoded Ca2+ indicator, has been associated with various side-effects. Here we unveil the intrinsic problem prevailing over different versions and applications, showing that GCaMP containing CaM (calmodulin) interferes with both gating and signaling of L-type calcium channels (CaV1). GCaMP acts as an impaired apoCaM and Ca2+/CaM, both critical to CaV1, which disrupts Ca2+ dynamics and gene expression. We then design and implement GCaMP-X, by incorporating an extra apoCaM-binding motif, effectively protecting CaV1-dependent excitation–transcription coupling from perturbations. GCaMP-X resolves the problems of detrimental nuclear accumulation, acute and chronic Ca2+ dysregulation, and aberrant transcription signaling and cell morphogenesis, while still demonstrating excellent Ca2+-sensing characteristics partly inherited from GCaMP. In summary, CaM/CaV1 gating and signaling mechanisms are elucidated for GCaMP side-effects, while allowing the development of GCaMP-X to appropriately monitor cytosolic, submembrane or nuclear Ca2+, which is also expected to guide the future design of CaM-based molecular tools. The popular genetically-encoded Ca2+ indicator, GCaMP, has several side-effects. Here the authors show that GCaMP containing CaM interferes with gating and signaling of L-type calcium channels, which disrupts Ca2+ dynamics and gene expression, and develop GCaMP-X to overcome these limitations.
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Affiliation(s)
- Yaxiong Yang
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China.,School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China.,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 102402, China.,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China
| | - Nan Liu
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China.,School of Life Sciences, Yunan University, Kunming, 650091, China
| | - Yuanyuan He
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China
| | - Yuxia Liu
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China
| | - Lin Ge
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China
| | - Linzhi Zou
- School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Sen Song
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China.,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China
| | - Wei Xiong
- IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China.,School of Life Sciences, Tsinghua University, Beijing, 100084, China
| | - Xiaodong Liu
- Department of Biomedical Engineering, School of Medicine, X-Lab for Transmembrane Signaling Research, Tsinghua University, Beijing, 100084, China. .,School of Biological Science and Medical Engineering, Beihang University, Beijing, 100083, China. .,Beijing Advanced Innovation Center for Biomedical Engineering, Beihang University, Beijing, 102402, China. .,IDG/McGovern Institute for Brain Research, Tsinghua University, Beijing, 100084, China. .,School of Life Sciences, Tsinghua University, Beijing, 100084, China. .,Key Laboratory for Biomedical Engineering of Education Ministry, Zhejiang University, Hangzhou, 310027, China.
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21
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Avenarius MR, Krey JF, Dumont RA, Morgan CP, Benson CB, Vijayakumar S, Cunningham CL, Scheffer DI, Corey DP, Müller U, Jones SM, Barr-Gillespie PG. Heterodimeric capping protein is required for stereocilia length and width regulation. J Cell Biol 2017; 216:3861-3881. [PMID: 28899994 PMCID: PMC5674897 DOI: 10.1083/jcb.201704171] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Revised: 07/21/2017] [Accepted: 08/08/2017] [Indexed: 02/07/2023] Open
Abstract
Control of the dimensions of actin-rich processes like filopodia, lamellipodia, microvilli, and stereocilia requires the coordinated activity of many proteins. Each of these actin structures relies on heterodimeric capping protein (CAPZ), which blocks actin polymerization at barbed ends. Because dimension control of the inner ear's stereocilia is particularly precise, we studied the CAPZB subunit in hair cells. CAPZB, present at ∼100 copies per stereocilium, concentrated at stereocilia tips as hair cell development progressed, similar to the CAPZB-interacting protein TWF2. We deleted Capzb specifically in hair cells using Atoh1-Cre, which eliminated auditory and vestibular function. Capzb-null stereocilia initially developed normally but later shortened and disappeared; surprisingly, stereocilia width decreased concomitantly with length. CAPZB2 expressed by in utero electroporation prevented normal elongation of vestibular stereocilia and irregularly widened them. Together, these results suggest that capping protein participates in stereocilia widening by preventing newly elongating actin filaments from depolymerizing.
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Affiliation(s)
- Matthew R. Avenarius
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Jocelyn F. Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Rachel A. Dumont
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Clive P. Morgan
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Connor B. Benson
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR
| | - Sarath Vijayakumar
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | | | | | - David P. Corey
- Department of Neurobiology, Harvard Medical School, Boston, MA
| | - Ulrich Müller
- Department of Neuroscience, Johns Hopkins University, Baltimore, MD
| | - Sherri M. Jones
- Department of Special Education and Communication Disorders, University of Nebraska-Lincoln, Lincoln, NE
| | - Peter G. Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, OR,Correspondence to Peter G. Barr-Gillespie:
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22
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Neuroplastin Isoform Np55 Is Expressed in the Stereocilia of Outer Hair Cells and Required for Normal Outer Hair Cell Function. J Neurosci 2017; 36:9201-16. [PMID: 27581460 DOI: 10.1523/jneurosci.0093-16.2016] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2016] [Accepted: 07/14/2016] [Indexed: 11/21/2022] Open
Abstract
UNLABELLED Neuroplastin (Nptn) is a member of the Ig superfamily and is expressed in two isoforms, Np55 and Np65. Np65 regulates synaptic transmission but the function of Np55 is unknown. In an N-ethyl-N-nitrosaurea mutagenesis screen, we have now generated a mouse line with an Nptn mutation that causes deafness. We show that Np55 is expressed in stereocilia of outer hair cells (OHCs) but not inner hair cells and affects interactions of stereocilia with the tectorial membrane. In vivo vibrometry demonstrates that cochlear amplification is absent in Nptn mutant mice, which is consistent with the failure of OHC stereocilia to maintain stable interactions with the tectorial membrane. Hair bundles show morphological defects as the mutant mice age and while mechanotransduction currents can be evoked in early postnatal hair cells, cochlea microphonics recordings indicate that mechanontransduction is affected as the mutant mice age. We thus conclude that differential splicing leads to functional diversification of Nptn, where Np55 is essential for OHC function, while Np65 is implicated in the regulation of synaptic function. SIGNIFICANCE STATEMENT Amplification of input sound signals, which is needed for the auditory sense organ to detect sounds over a wide intensity range, depends on mechanical coupling of outer hair cells to the tectorial membrane. The current study shows that neuroplastin, a member of the Ig superfamily, which has previously been linked to the regulation of synaptic plasticity, is critical to maintain a stable mechanical link of outer hair cells with the tectorial membrane. In vivo recordings demonstrate that neuroplastin is essential for sound amplification and that mutation in neuroplastin leads to auditory impairment in mice.
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23
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Cunningham CL, Wu Z, Jafari A, Zhao B, Schrode K, Harkins-Perry S, Lauer A, Müller U. The murine catecholamine methyltransferase mTOMT is essential for mechanotransduction by cochlear hair cells. eLife 2017; 6:e24318. [PMID: 28504928 PMCID: PMC5462538 DOI: 10.7554/elife.24318] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Accepted: 05/14/2017] [Indexed: 12/26/2022] Open
Abstract
Hair cells of the cochlea are mechanosensors for the perception of sound. Mutations in the LRTOMT gene, which encodes a protein with homology to the catecholamine methyltransferase COMT that is linked to schizophrenia, cause deafness. Here, we show that Tomt/Comt2, the murine ortholog of LRTOMT, has an unexpected function in the regulation of mechanotransduction by hair cells. The role of mTOMT in hair cells is independent of mTOMT methyltransferase function and mCOMT cannot substitute for mTOMT function. Instead, mTOMT binds to putative components of the mechanotransduction channel in hair cells and is essential for the transport of some of these components into the mechanically sensitive stereocilia of hair cells. Our studies thus suggest functional diversification between mCOMT and mTOMT, where mTOMT is critical for the assembly of the mechanotransduction machinery of hair cells. Defects in this process are likely mechanistically linked to deafness caused by mutations in LRTOMT/Tomt.
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Affiliation(s)
- Christopher L Cunningham
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, United States
| | - Zizhen Wu
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, United States
| | - Aria Jafari
- Department of Surgery, University of California, San Diego, San Diego, United States
| | - Bo Zhao
- Department of Otolaryngology Head and Neck Surgery, Indiana University School of Medicine, Indianapolis, United States
| | - Kat Schrode
- Department of Otolaryngology, Johns Hopkins University, Baltimore, United States
| | - Sarah Harkins-Perry
- Department of Molecular and Cellular Biology, The Scripps Research Institute, La Jolla, United States
| | - Amanda Lauer
- Department of Otolaryngology, Johns Hopkins University, Baltimore, United States
| | - Ulrich Müller
- The Solomon Snyder Department of Neuroscience, Johns Hopkins University, Baltimore, United States
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24
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Pejvakin, a Candidate Stereociliary Rootlet Protein, Regulates Hair Cell Function in a Cell-Autonomous Manner. J Neurosci 2017; 37:3447-3464. [PMID: 28209736 DOI: 10.1523/jneurosci.2711-16.2017] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 01/02/2017] [Accepted: 01/25/2017] [Indexed: 11/21/2022] Open
Abstract
Mutations in the Pejvakin (PJVK) gene are thought to cause auditory neuropathy and hearing loss of cochlear origin by affecting noise-induced peroxisome proliferation in auditory hair cells and neurons. Here we demonstrate that loss of pejvakin in hair cells, but not in neurons, causes profound hearing loss and outer hair cell degeneration in mice. Pejvakin binds to and colocalizes with the rootlet component TRIOBP at the base of stereocilia in injectoporated hair cells, a pattern that is disrupted by deafness-associated PJVK mutations. Hair cells of pejvakin-deficient mice develop normal rootlets, but hair bundle morphology and mechanotransduction are affected before the onset of hearing. Some mechanotransducing shorter row stereocilia are missing, whereas the remaining ones exhibit overextended tips and a greater variability in height and width. Unlike previous studies of Pjvk alleles with neuronal dysfunction, our findings reveal a cell-autonomous role of pejvakin in maintaining stereocilia architecture that is critical for hair cell function.SIGNIFICANCE STATEMENT Two missense mutations in the Pejvakin (PJVK or DFNB59) gene were first identified in patients with audiological hallmarks of auditory neuropathy spectrum disorder, whereas all other PJVK alleles cause hearing loss of cochlear origin. These findings suggest that complex pathogenetic mechanisms underlie human deafness DFNB59. In contrast to recent studies, we demonstrate that pejvakin in auditory neurons is not essential for normal hearing in mice. Moreover, pejvakin localizes to stereociliary rootlets in hair cells and is required for stereocilia maintenance and mechanosensory function of the hair bundle. Delineating the site of the lesion and the mechanisms underlying DFNB59 will allow clinicians to predict the efficacy of different therapeutic approaches, such as determining compatibility for cochlear implants.
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25
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Morgan CP, Krey JF, Grati M, Zhao B, Fallen S, Kannan-Sundhari A, Liu XZ, Choi D, Müller U, Barr-Gillespie PG. PDZD7-MYO7A complex identified in enriched stereocilia membranes. eLife 2016; 5:e18312. [PMID: 27525485 PMCID: PMC5005036 DOI: 10.7554/elife.18312] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2016] [Accepted: 08/14/2016] [Indexed: 12/15/2022] Open
Abstract
While more than 70 genes have been linked to deafness, most of which are expressed in mechanosensory hair cells of the inner ear, a challenge has been to link these genes into molecular pathways. One example is Myo7a (myosin VIIA), in which deafness mutations affect the development and function of the mechanically sensitive stereocilia of hair cells. We describe here a procedure for the isolation of low-abundance protein complexes from stereocilia membrane fractions. Using this procedure, combined with identification and quantitation of proteins with mass spectrometry, we demonstrate that MYO7A forms a complex with PDZD7, a paralog of USH1C and DFNB31. MYO7A and PDZD7 interact in tissue-culture cells, and co-localize to the ankle-link region of stereocilia in wild-type but not Myo7a mutant mice. Our data thus describe a new paradigm for the interrogation of low-abundance protein complexes in hair cell stereocilia and establish an unanticipated link between MYO7A and PDZD7.
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Affiliation(s)
- Clive P Morgan
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
| | - Jocelyn F Krey
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
| | - M'hamed Grati
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
| | - Bo Zhao
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, United States
| | - Shannon Fallen
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
| | | | - Xue Zhong Liu
- Department of Otolaryngology, Miller School of Medicine, University of Miami, Miami, United States
| | - Dongseok Choi
- OHSU-PSU School of Public Health, Oregon Health and Science University, Portland, United States
- Graduate School of Dentistry, Kyung Hee University, Seoul, Korea
| | - Ulrich Müller
- Dorris Neuroscience Center, The Scripps Research Institute, La Jolla, United States
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center and Vollum Institute, Oregon Health and Science University, Portland, United States
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26
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Abstract
UNLABELLED Disordered protein ubiquitination has been linked to neurodegenerative disease, yet its role in inner ear homeostasis and hearing loss is essentially unknown. Here we show that progressive hearing loss in the ethylnitrosourea-generated mambo mouse line is caused by a mutation in Usp53, a member of the deubiquitinating enzyme family. USP53 contains a catalytically inactive ubiquitin-specific protease domain and is expressed in cochlear hair cells and a subset of supporting cells. Although hair cell differentiation is unaffected in mambo mice, outer hair cells degenerate rapidly after the first postnatal week. USP53 colocalizes and interacts with the tight junction scaffolding proteins TJP1 and TJP2 in polarized epithelial cells, suggesting that USP53 is part of the tight junction complex. The barrier properties of tight junctions of the stria vascularis appeared intact in a biotin tracer assay, but the endocochlear potential is reduced in adult mambo mice. Hair cell degeneration in mambo mice precedes endocochlear potential decline and is rescued in cochlear organotypic cultures in low potassium milieu, indicating that hair cell loss is triggered by extracellular factors. Remarkably, heterozygous mambo mice show increased susceptibility to noise injury at high frequencies. We conclude that USP53 is a novel tight junction-associated protein that is essential for the survival of auditory hair cells and normal hearing in mice, possibly by modulating the barrier properties and mechanical stability of tight junctions. SIGNIFICANCE STATEMENT Hereditary hearing loss is extremely prevalent in the human population, but many genes linked to hearing loss remain to be discovered. Forward genetics screens in mice have facilitated the identification of genes involved in sensory perception and provided valuable animal models for hearing loss in humans. This involves introducing random mutations in mice, screening the mice for hearing defects, and mapping the causative mutation. Here, we have identified a mutation in the Usp53 gene that causes progressive hearing loss in the mambo mouse line. We demonstrate that USP53 is a catalytically inactive deubiquitinating enzyme and a novel component of tight junctions that is necessary for sensory hair cell survival and inner ear homeostasis.
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27
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Helios(®) Gene Gun-Mediated Transfection of the Inner Ear Sensory Epithelium: Recent Updates. Methods Mol Biol 2016; 1427:3-26. [PMID: 27259918 DOI: 10.1007/978-1-4939-3615-1_1] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The transfection of vertebrate inner ear hair cells has proven to be challenging. Therefore, many laboratories attempt to use and improve different transfection methods. Each method has its own advantages and disadvantages. A particular researcher's skills in addition to available equipment and the type of experiment (in vivo or in vitro) likely determine the transfection method of choice. Biolistic delivery of exogenous DNA, mRNA, or siRNA, also known as Helios(®) Gene Gun-mediated transfection, uses the mechanical energy of compressed helium gas to bombard tissue with micron- or submicron-sized DNA or RNA-coated gold particles, which can penetrate and transfect cells in vitro or in vivo. Helios(®) Gene Gun-mediated transfection has several advantages: (1) it is simple enough to learn in a short time; (2) it is designed to overcome cell barriers even as tough as plant cell membrane or stratum corneum in the epidermis; (3) it can transfect cells deep inside a tissue such as specific neurons within a brain slice; (4) it can accommodate mRNA, siRNA, or DNA practically of any size to be delivered; and (5) it works well with various cell types including non-dividing, terminally differentiated cells that are difficult to transfect, such as neurons or mammalian inner ear sensory hair cells. The latter advantage is particularly important for inner ear research. The disadvantages of this method are: (1) low efficiency of transfection due to many variables that have to be adjusted and (2) potential mechanical damage of the tissue if the biolistic shot parameters are not optimal. This chapter provides a step-by-step protocol and critical evaluation of the Bio-Rad Helios(®) Gene Gun transfection method used to deliver green fluorescent protein (GFP)-tagged full-length cDNAs of myosin 15a, whirlin, β-actin, and Clic5 into rodent hair cells of the postnatal inner ear sensory epithelia in culture.
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28
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Abstract
Hearing loss (HL) is one of the most common birth defects in developed countries and is a diverse pathologic condition with different classifications. One of these is based on the association with other clinical features, defined as syndromic hearing loss (SHL). Determining the cause of the HL in these patients is extremely beneficial as it enables a personalized approach to caring for the individual. Early screening can further aid in optimal rehabilitation for a child's development and growth. The advancement of high-throughput sequencing technology is facilitating rapid and low-cost diagnostics for patients with SHL.
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Affiliation(s)
- Tal Koffler
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Kathy Ushakov
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel
| | - Karen B Avraham
- Department of Human Molecular Genetics and Biochemistry, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv University, Tel Aviv 6997801, Israel.
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29
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Abstract
Hearing loss is the most common form of sensory impairment in humans and affects more than 40 million people in the United States alone. No drug-based therapy has been approved by the Food and Drug Administration, and treatment mostly relies on devices such as hearing aids and cochlear implants. Over recent years, more than 100 genetic loci have been linked to hearing loss and many of the affected genes have been identified. This understanding of the genetic pathways that regulate auditory function has revealed new targets for pharmacological treatment of the disease. Moreover, approaches that are based on stem cells and gene therapy, which may have the potential to restore or maintain auditory function, are beginning to emerge.
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Affiliation(s)
- Ulrich Müller
- Department of Molecular and Cellular Neuroscience, Dorris Neuroscience Center, The Scripps Research Institute, 10550 North Torrey Pines Road, La Jolla, San Diego, California 92037, USA
| | - Peter G Barr-Gillespie
- Oregon Hearing Research Center, Vollum Institute, Oregon Health &Science University, 3181 South West Sam Jackson Park Road, Portland, Oregon 97239, USA
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30
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Subunit determination of the conductance of hair-cell mechanotransducer channels. Proc Natl Acad Sci U S A 2014; 112:1589-94. [PMID: 25550511 DOI: 10.1073/pnas.1420906112] [Citation(s) in RCA: 111] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Cochlear hair cells convert sound stimuli into electrical signals by gating of mechanically sensitive ion channels in their stereociliary (hair) bundle. The molecular identity of this ion channel is still unclear, but its properties are modulated by accessory proteins. Two such proteins are transmembrane channel-like protein isoform 1 (TMC1) and tetraspan membrane protein of hair cell stereocilia (TMHS, also known as lipoma HMGIC fusion partner-like 5, LHFPL5), both thought to be integral components of the mechanotransduction machinery. Here we show that, in mice harboring an Lhfpl5 null mutation, the unitary conductance of outer hair cell mechanotransducer (MT) channels was reduced relative to wild type, and the tonotopic gradient in conductance, where channels from the cochlear base are nearly twice as conducting as those at the apex, was almost absent. The macroscopic MT current in these mutants was attenuated and the tonotopic gradient in amplitude was also lost, although the current was not completely extinguished. The consequences of Lhfpl5 mutation mirror those due to Tmc1 mutation, suggesting a part of the MT-channel conferring a large and tonotopically variable conductance is similarly disrupted in the absence of Lhfpl5 or Tmc1. Immunolabelling demonstrated TMC1 throughout the stereociliary bundles in wild type but not in Lhfpl5 mutants, implying the channel effect of Lhfpl5 mutations stems from down-regulation of TMC1. Both LHFPL5 and TMC1 were shown to interact with protocadherin-15, a component of the tip link, which applies force to the MT channel. We propose that titration of the TMC1 content of the MT channel sets the gradient in unitary conductance along the cochlea.
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Zhao B, Wu Z, Grillet N, Yan L, Xiong W, Harkins-Perry S, Müller U. TMIE is an essential component of the mechanotransduction machinery of cochlear hair cells. Neuron 2014; 84:954-67. [PMID: 25467981 DOI: 10.1016/j.neuron.2014.10.041] [Citation(s) in RCA: 155] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/15/2014] [Indexed: 12/18/2022]
Abstract
Hair cells are the mechanosensory cells of the inner ear. Mechanotransduction channels in hair cells are gated by tip links. The molecules that connect tip links to transduction channels are not known. Here we show that the transmembrane protein TMIE forms a ternary complex with the tip-link component PCDH15 and its binding partner TMHS/LHFPL5. Alternative splicing of the PCDH15 cytoplasmic domain regulates formation of this ternary complex. Transducer currents are abolished by a homozygous Tmie-null mutation, and subtle Tmie mutations that disrupt interactions between TMIE and tip links affect transduction, suggesting that TMIE is an essential component of the hair cell's mechanotransduction machinery that functionally couples the tip link to the transduction channel. The multisubunit composition of the transduction complex and the regulation of complex assembly by alternative splicing is likely critical for regulating channel properties in different hair cells and along the cochlea's tonotopic axis.
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Affiliation(s)
- Bo Zhao
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Zizhen Wu
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Nicolas Grillet
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Linxuan Yan
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Wei Xiong
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Sarah Harkins-Perry
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Ulrich Müller
- Dorris Neuroscience Center, Department of Molecular and Cellular Neuroscience, The Scripps Research Institute, 10550 N. Torrey Pines Road, La Jolla, CA 92037, USA.
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